Have you ever had a CO2 infused planted aquarium and for a while everything went just right? You had no problems, things were doing well, no algae and you felt pretty pleased with yourself :). In fact, you had temporarily nailed it and then...
So you rack your brain, think about what has changed and what might have happened but you still draw a blank. The answer is that you have probably become a victim of your own success (or at least your tank has). As your tank matures, plants grow. This means that the increased biomass effects water distribution along with the plants requiring more fertilisers. If you have kept your CO2 levels the same as before and you're still adding the same amount of fertilisers as before, you can begin to see why the problem has evolved. Slowly but surely you've been starving your plants of what they really need:
- More CO2
- More Fertilisers
- Better Water Distribution
The best thing to do at this stage is to give your plants a good haircut. This will bring overall levels back to where they were (when the tank was doing great). Any deformed leaves or one's which have algae on them should be chopped off. Essentially you are resetting your aquarium and now you know better. It's important to stress that as your tank grows you have to increase CO2, fertilisers and improve water flow. Larger plants will block water in its path and stop essential nutrients from getting where they used to. Pay attention to what your plants are telling you - observe your CO2 bubbles and see if they are getting to everywhere that they should. This is the beauty about using pressurised CO2 as you can watch the tiny bubbles move around the tank and if they're not getting to a certain area, then you can bet fertilisers aren't either.
In summary, it's easy to overlook the correlation between plants growing and the effect this has on your planted aquarium. Just remember that as they grow, more demands are put on the aquarium unless you maintain the plants to a specific size (trimming weekly for example).
Have you had problems with your aquarium and overcome them? I'd love to here them.